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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Posted on 22 December 2011 by Rob Painting

Fossil fuel-burning is acidifying the oceans and, up until recently, it has generally been thought that the greatest risk posed by ocean acidification was the change to seawater carbon chemistry. This is because rising levels of atmospheric carbon dioxide reduce the concentration of seawater carbonate ions, a vital building-block in the shells and skeletons of many marine life. Fish were not thought to be at direct risk from acidification, because they clearly don't build shells, and were considered to have well-developed physical mechanisms to tolerate falling pH (acidification).

Several studies published in the journal Nature Climate Change, Baumann (2011) and Frommel (2011), indicate that this might not be the case. Fish may, in fact, be seriously threatened by ocean acidification. Although adult fish seem well-equipped to deal with low pH waters, or higher levels of CO2 in seawater, their egg and larval life stages, a typically vulnerable time for all marine life, may not be so fortunate.

Baumann (2011) show that larvae survival in one fish species drops with increased levels of CO2 (figure 1). Survival rates plummeting some 75% under a scenario with 1000ppm (parts per million) of atmospheric CO2. And Frommel (2011) discovered considerable tissue damage and necrosis (dead tissue) in fish larvae of another species exposed to higher levels of CO2 than the present day. In the high CO2 experiments, this damage to internal organs was so extensive it lead to the death of afflicted larvae. Each of these studies are discussed in detail below.

Baumann (2011) conducted a series of experiments where CO2 was bubbled into seawater containing the newly-fertilized eggs of the inland silverside. Larvae were exposed to levels of acidification representative of modern-day (390-400ppm,) right up to projected late 21st century (900-1100ppm) atmospheric CO2 levels. After a week the surviving larvae were counted and measured.

In each of the 5 experiments both the larvae body length and survival rates declined as seawater became more acidified (figure 1), and there were also more deformed larvae (figure 2).

Figure 2- Larvae with curved or curled bodies were significantly more common at increased (b,c) when compared with control (a) CO2 levels. Scale bar=1 mm.

At 1000 ppm, survival plunged some 75% and larval body length 18%. The shorter length indicates a slower rate of growth, a problem for larvae because the longer the time they spend growing in their larval stage, the higher the rate of predation by plankton-eating fish and other critters. In other words, slower growth and larval deformities will likely translate into even lower survival rates in the wild, compounding the death rate of these larvae as ocean acidification increases.

The cause of this slow growth, deformation and decline in survival rates in the experiments is not known, but given that inland silverside can grow and thrive in more acidified freshwater, this suggests something other than pH. Baumann (2011) suggest this may be related to high CO2 levels, or even the carbonate chemistry of the water.

The authors speculated that the negative response may have been related to the susceptibility of very early larval development, the egg embryo, so carried out another experiment, After growing in seawater equivalent to 410 ppm for 5 days, fertilized eggs were exposed to 780ppm once they hatched. Survival rates only slightly dropped in this treatment versus the control (at constant 410 ppm), and survival was much higher than larvae exposed to 780 ppm the entire time, suggesting that it's the eggs themselves that may be vulnerable to ocean acidification.

The cod larvae for this experiment were taken from a population off Norway, and were exposed to 3 levels of seawater acidity equivalent to 380 ppm (the control), 1800 ppm (medium) and 4200 ppm (high). Although these last two scenarios may seem very high, Kiel Fjord (noted earlier) is very near to Baltic cod spawning grounds and already sees levels above the equivalent of 1800ppm, and is likely to endure acidification comparable to around 4200 ppm with a doubling of atmsopheric CO2 (560 ppm). So the experiments are directly relevant to current and near-future conditions in which Atlantic cod spawn.

Cod larvae were reared for 7 weeks in large outdoor cylinders called mesocosms. The authors did not directly test for mortality (death rate), but instead looked for changes in tissue health. They discovered that in the early stages of development, the first 25 days after hatching was a critical time. Newly-hatched larvae lack fully-functioning gills, which is the primary organ for helping regulate internal pH balance and CO2 build up in tissue. In this early development stage the larvae are essentially at the mercy of the surrounding seawater pH, and are therefore very vulnerable. In the experiment, larvae suffered extensive damage to vital organs with rising acidity, and those larvae with extreme malformations to internal organs and widespead dead tissue, obviously died from these deformities. See figure 3.

The effect of the three acidity scenarios on larval tissue are is shown in figure 4. As acidity increases, so too does the amount of tissue damage.

Figure 4 - Percentage of larvae exhibiting different degrees of total damage at 32 and 46 days after hatching and three different treatment levels (control, medium and high). The damage is shown as five levels with normal as white bars, and shading increasing with increasing severity of damage. Control=380ppm, medium=1800ppm and high=4200ppm.

In the summary of their paper the authors conclude:

"Although we did not directly test for mortality rates, our data on severe tissue damage suggest that ocean acidification will negatively impact the recruitment of mass-spawning fishes because of enhanced mortality rates."

Fish flunk the acid test too

To sum up:

The Baumann (2011) and Frommel (2011) studies are surprising in that they reveal that rather than being impervious to the effects of ocean acidification, as earlier believed, higher levels of acidification are actually fatal to fish in their early life stages (egg/larval form).

Both the severity of tissue damage to major internal organs, and the mortality rate in fish larvae increase along with rising levels of CO2.

The high CO2 scenarios in the experiments are representative of both current day and near-future conditions found in some regions where these fish spawn. So the results suggest ocean acidification may be having an impact on these species today.

Further tests will be necessary to determine how widespread this egg/larval susceptibility is among fish species, but if the results of these studies are an indication of the harm ocean acidification causes to fish life in general, then along with overfishing, pollution and habitat contraction (a consequence of warming seawater and ocean acidification) we may begin to see major fish stocks collapse.

Comments

Really good post Rob, but rather disturbing that we keep finding new unintended consequences of anthropogenic climate change. A lot of people rely heavily on fish for food - decreasing stocks due to acidification would be really bad news.

The oceans form a pH-buffered system. This means (check your lower grade chemistry lessons) that large changes in CO2-concentration will result in small changes in pH. The present pH-change is insignificant. Predictions of extreme pH-changes are incredible. Not much to worry about.

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Moderator Response: Your comment demonstrates you have not read our extensive OA not OK series. Please read this before commenting further. I consider your comment to be trolling and will delete further trolling without notice. [Doug]
[muon] fixed link

fyd.. and where is that buffer coming from in shallow water where these fish babies are? oh yes, mainly the shells of reef forming organisms. slowly, and patchily. so it's quite possible to get extreme acidity locally, as mentioned in the article. the 'steady state' model just doesn't fit on less than geological time scales or smaller than ocean wide geographical scales.

The only problem with this analysis is the CO2 level used are on the extreme high end of the possible. From the data they give, actual high CO2 concentration are not cause by the increase of atmospheric CO2. However, increase of organics matter in ocean due to fertilizer run-off my increase it.

increasing water temperature results in lower solubility of CO2 in the oceans.

The net result is less not more CO2 in the water - some well qualified scientists even say the increases in water temperatures observed are responsible for most of the atmospheric increases in CO2 levels.

There are numerous references including US government agencies which claim natural sources of atmospheric CO2 are far larger than manmade releases.

Either way, no matter what you believe the fact remains -

CO2 is less soluble in warm water and rapidly escapes to the atmosphere.

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Moderator Response: [Rob P] Do yourself a favor and read the rather extensive SkS series OA is not OK which is written by actual experts on the topic. The warming oceans will make relatively little difference to CO2 uptake by the oceans.

Yvan -"The only problem with this analysis is the CO2 level used are on the extreme high end of the possible"

That's not correct. 2300ppm (equivalent) is already experienced over summer and autumn in Kiel Fjord, an area close to cod spawning grounds. This was pointed out in the post. If you look at figure 4 (medium =1800ppm scenario), you'll notice an increase in cod larvae tissue damage and, undoubtedly, a consequent increase in mortality.

Also, many regions along the Atlantic coast of North America (home of the inland silverside studied in Baumann [2011]) are seeing acidification much worse than anticipated. In other words, ocean acidification is very likely affecting these fish egg/larvae today.

fydijkstra many fish are sensitive to even small changes in ph levels even if it doesn't kill them. The question then is whether species would adapt or would migrate. But why conduct a massive experiment with CO2 emissions just to find out what happens?

Rosco--You are correct about CO2 solubility as a function of temperature, but that effect will be totally overwhelmed by the other equilibria considerations. As with any gas-liquid interface with a soluble gas, the system will always attempt to reach equilibrium, and be concurrently losing gas out of solution from the water and absorbing gas from the air. Increased water temperature will shift that equilibrium point to lower net CO2 absorption. In the past century or so, the overall water temperature has increased overall roughly a degree or so. The concentration of CO2 in the atmosphere has increased by nearly 50%. All other things being equal, the net absorption into the water will increase because of the increased concentration and it will try to reach its new equilibrium point based on that, with a slight modification because of increased temperature.

Your argument about all CO2 increases due to water temperature increases, well, doesn't hold water (sorry). There isn't enough CO2 in the ocean to "boil off" like that with a small temperature change, aside from the inconvenient increases in the CO2/carbonate/acidity concentrations. If the overall system was that sensitive to temperature, we would see very high CO2 concentrations in the tropics since the CO2 would leave, and very low levels in the northern oceans. In actuality we only see only a couple ppm difference, and most of that seems to be a result of delays in mixing from sources to lower concentration areas.

As for "government agencies" and their claims, I think we need to see specific citations and contexts. The natural sources are huge, but when we put the system out of balance and have system response times measured in centuries, it will take time to get back to equilibrium. In the meantime, the climate changes and the oceans become more acidic.

Westerwick @9, I believe Rosco is referring to the fact that CO2 at the Earth's surface is held in three large reservoirs, the upper ocean, the atmosphere and the biosphere. Exchanges between these reservoirs dwarf any additions to the total system by humans. Of course, all three systems are in effective equilibrium, so that net flux between any two reservoirs is close to zero. To increase the amount of CO2 in all three reservoirs requires CO2 from another source, and human emissions dwarf all natural emissions from other sources. Of course, the full facts of the matter have been carefully concealed from (or by) Rosco to create a misleading impression.

Of course, you are aware that those 'natural sources' have been in place for a long, long time. So long that an equilibrium known as the Carbon Cycle is well-established and well-known. So those 'natural sources' aren't part of this problem; the folks that dumped a large mass of carbon into the atmosphere in under 200 years; more than half of that in the last 60 years - that's the problem.

Rob Painting @7, I think it should be made clear that high levels of carbonate and bicarbonate in Norwegian seas relative to current atmospheric levels of CO2 is because of the cold water absorbs more CO2. Therefore colder waters will be more acid for a given CO2 concentration than will warmer waters, as can be seen below:

It is not because of unusually high CO2 concentrations in the atmosphere above Norway, or because of local water pollution.

Tom, cold water being able to absorb more CO2 is definitely part of the answer, but so too is eutrophication - where nutrient run-off from agriculture (mainly) ramps up phytoplankton growth (they're surface-dwelling marine plants).

During phytoplankton blooms, large volumes of CO2 are utilized as phytoplankton absorb CO2 into organic tissue. When they die a week or so later, they fall to the ocean floor and are broken down by bacteria, thereby releasing the CO2 they stored in their tissue (remineralization). This makes the ocean floor seawater more acidified. The 'Biological Carbon Pump' was discussed in the SkS post Ocean Acidification: Corrosive waters arrive in the Bering Sea

And another culprit is increased upwelling in some regions in response to ocean circulation changes brought on by global warming. These processes acting together are rapidly acidfying the subsurface ocean in cooler regions of the globe, and are also de-oxygenating these areas.

Anyway, I have future ocean acidification posts covering these topics.

Atlantic Cod stocks have taken a beating in a lot of their range. A large part of the current fishery takes place in Iceland. There is a very good pH dataset for the Iceland Sea(Olafsson 2009) the aragonite saturation horizon is at about 1700 meters and shoaling four meters a year but it is still a long way from the 600 meter depth range of Atlantic Cod. There is never good news in OA but the fact that Atlantic Cod are a very large aqua-culture fishery in Norway means the sensitivity of Cod eggs and juvenile fish to elevated pCO2 will be studied carefully. Maybe like the oyster industry in the Northeastern Pacific agua-culture will find some ability to adapt. For fishermen like me who are dependent on wild stocks the effects of O/A will much more difficult. We will be somewhat tethered to what aqua-culture can learn about our mutual problems. Bruce

Great post. I'm impressed with the apparently high variance among larvae in damage (Figure 4). It would be useful to find out how much of this was additive genetic variance, and therefore learn something about potential of populations to evolve in response to this stressor as it worsens.

Hi guys, another great post. I'm having a little difficulty understanding this, however. Fish first emerged about 510 million years ago, and we've had warming periods much greater than present day (up to 7C anomaly at the highest extreme) since then. As we know CO2 is correlated with global warming, we know that CO2 must have been at much higher levels than 1000ppm during those periods of high temperature. Yet we still have fish.

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Response:

[DB] You are missing the fundamental point that the rate of change is the issue with today's human-induced climate change. The rate of CO2 injection into the atmosphere is more than 10x that which occurred during the PETM, the most comparable period in Earth's history. And, as you point out, CO2 is correlated with global warming (and cooling).

mace @ 19: We still have fish, but none of the species we had 510 million years ago. They all went extinct due to environmental change, negative interactions with other species, etc.

Nobody is arguing that anthropogenic climate change will completely exterminate life on the planet. Acidification might not even cause the species used in the experiments Rob described to go extinct. However, based on the results, their populations would likely be reduced, greatly.

Steve L @ 17: Great question. This would be really hard to tease out with this system and some of the variance is surely non-genetic experimental noise (or demonic intrusion). I am working with two colleagues here at UNC to look at this with coral, which, due to their clonal nature, we can fragment to create a large number of replicates of the same genotype that we then expose to different temperature and pH treatments. (the small colonies of the same genotype are called "ramets") We just completed an experiment, and when analyzing the data will look for genotype by environment interactions, essentially testing if different genotypes reacted more strongly (or more weakly) to the experimental treatments. To do all this, you need to expose the same genotype (with replication) to multiple treatments - hard to do with most vertebrates unless you have a model system like mice with inbred lines in which there is little genetic variance among species. I suspect we will find variance for response to pH, but that doesn't necc. mean populations will be abale to evolve adaptively without costs, due to tradeoffs, etc.

mace @ 20: If you had a giant time machine and transported all of the extant (google it) fishes to the Cambrian, most would go extinct. The fact that life existed in the past when the land and seas were very different does not mean there would/will be no effect on life if we recreate those conditions today. Cambrian species evolved to exist in a Cambrian world, extant species aren't.

Thanks JohnBruno, I'm just a bit lost as to what this article is trying to tell us. If the climate had never changed, we'd still have dinosaurs. Obviously, when conditions change, some species die, some flourish. I don't know what the point of this scientist was killing fish just to point out the bleeding obvious. What's his next experiment, setting fire to a cat?

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Response:

[DB] "Obviously, when conditions change, some species die, some flourish."

Your concerns are better addressed on the Climate's changed before thread. Please avoid statements such as your last, which adds nothing to the dialogue and is largely interpretable as trolling.

mace @19 &20, as already indicated by John Bruno, what is different is that modern fish have adapted to pre-industrial conditions of low CO2 concentration.

What he has not given you is the appropriate perspective on time. To gain that, consider the problem of lactose intolerance in humans. The important thing here is that cows milk, which is rich in lactose, is a readily available food source rich in nutrition and very commonly used in Europe. Being unable to use milk or milk products represents a major problem, and in pre-industrial times a significant impediment to survival. Cattle where first domesticated some 9 thousand years ago. The original Indo-European language (the language of the ancestors of nearly all Europeans) included a word for cattle. So Europeans have been relying on cattle, and cattle products, especially milk for around 4 thousand years at least. Yet there are still Europeans who are lactose intolerant. Four thousand years is insufficient time to fully evolve lactose tolerance in the the European population.

Fish will not have 4 thousand years to evolve adaptability to high CO2 concentrations. They have had only 150 years so far to adapt to rising CO2 levels, and will have 100 to 150 more at most given BAU to adapt to levels which are currently severely damaging. The only way populations can evolve that fast is by crashing, ie, to reducing down to the very few individuals that may be currently tolerant, and then gradually rebuilding population levels. The problem with this approach is that if a population crashes, there is no guarantee that it will rebuild. Indeed, given the results discussed in the article above, many species of fish may be on their way to extinction, and possibly many regions of the Oceans will become fish free for perhaps centuries (if we are lucky) or millenia (if we are not). That is not guaranteed to happen, but it is a realistic possibility on current data.

The contrast with natural changes in CO2 levels is that the large changes have occurred over millions of years, thereby giving animal species time to evolve new traits and to adapt to the new conditions. If we also where raising CO2 levels at a rate of 1 ppm per millenium or less, than we to would have little to worry about in terms of biological adaption. On the other hand, when nature has caused CO2 levels to rise rapidly (on 10 thousand year time scales) wide spread extinctions have always occurred. Given that we are raising CO2 levels at 100 times that rate (and 10,000 times the normal rate of natural change), we have no reason for confidence.

What we need to be doing is to improve our models so that the skeptic-deniers don't have any ammunition. The previous article which shows that removing the effects of solar irradiance, aerosols and ENSO keeps us on track for a constantly warming planet is, in my opinion, the way forward.

mace @23, what the article tells us is that high CO2 levels are in and of themselves something fish need to adapt to. It has previously been known that many fish species are threatened by the probably loss of coral reefs, and of many species of planckton which will be adversely effected by high CO2 levels. That lead to risks to fish populations due to starvation (among other causes). But we now know fish themselves face direct adversity from rising CO2 levels.

Thanks, it would be useful, if the chart located here
http://en.wikipedia.org/wiki/Paleoclimatology

showed how today compares with the rest of known history. skeptic-deniers can point to the spikes that occurred during the pleistocene period as being greater than what happened today, for example, a period during which humans emerged as a species
http://en.wikipedia.org/wiki/Pleistocene

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Response:

[DB] "skeptic-deniers can point to the spikes that occurred during the pleistocene period as being greater than what happened today"

You mean as you are doing now? Your concerns are better addressed in the Climate's changed before thread. And you are incorrect for multiple reasons. Please read the referenced thread and place any remaining concerns there.

I see your point DB. Sorry, I just want to arm myself as much as possible to combat some denialist rubbish coming my way at the moment. Please don't put me in the same bucket as those nutcases.

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Response:

[DB] "Please don't put me in the same bucket as those nutcases."

I do not. However, repeating a meme gives it undeserved life. Perhaps a slight rephrasing of your statements would be more effective:

"One thing that I've heard repeated in some circles is that the temperature and CO2 spikes that occurred during the Pleistocene period were greater than what is happening today. Can someone help me understand why this statement isn't true or relevant to today?"

The cause of this slow growth, deformation and decline in survival rates in the experiments is not known, but given that inland silverside can grow and thrive in more acidified freshwater, this suggests something other than pH. Baumann (2011) suggest this may be related to high CO2 levels, or even the carbonate chemistry of the water.

I'm not sure that I'd completely dismiss pH itself as a contributor to altered growth and/or development in all marine fish.

It has been known for many decades that the eggs/zygotes/larvae of many freshwater fish are exquisitely sensitive to hydronium ion concentration. Ask any serious breeder of some of the finnicky South American characins for a start - although the phenomenon is recognised in many taxa. Ironically, in fresh water it is often acid-loving species that are sensitive to changes in pH.

Certainly carbonates and other salt species are enormously conspicuous components of the saltwater chemical milieu, and quite possibly dominate most piscine physiological responses to varying concentrations of dissolved ions, but hydronium itself is physiologically important. Changing its concentration in an environment that it extremely consistent by ecophysiological standards is quite possibly going to affect sensitive growth stages of at least some marine fish species, either by itself or in concert with coincident chemical changes arising from increase in ocean carbonic acid concentration.

Whatever the mechanism, it should come as no surprise to most fish physiologists that pH will tend to target the early life-stages of fish. I've been speaking of such vulnerability for years, and I suspect that in a few more decades, should carbon emission control remain as limp as it has been to date, there will be a recognised crash in recruitment to quite a few important (and many not-so-important) marine fish stocks, arising directly from physiologial mal-adaptation to altered hydronium ion concentration.

The results of both the cited works are very precise and should be simply to accept. The facts are not discussed, but ...
... but in no case, however, they authorize author's post above - R.P. - the title of post: “Ocean Acidification Is Fatal To Fish“

How can acidification affect fisheries?
• Through recruitment
– Early life stages of fish (eggs, larvae) are likely to be
vulnerable to change in pH
– Changes in the plankton community may reduce
survival in the early life stages due to:
• Food quality
• Food quantity
• Timing – match/mismatch
• Predation

We are now facing a future with lower pH and higher CO2 that in combination with a rising temperature most likely will be unfavourable - at least for some species in some ecosystems.”

... but even these conclusions are there too, and such general - very important - the main comments:

„Acidification – Effects on fish stocks and fisheries:• Nature and degree of effects are largely unknown
• Both direct and indirect effects are anticipated
• Effects likely to be highly diverse, depending on, i.a.,
ecosystem, fish species, state of exploitation• Effects may be confounded by effects of climate change
and overfishing”

To this I add Hoffmann & Sgrò (2011): “Evolutionary adaptation can be rapid and potentially help species counter stressful conditions or realize ecological opportunities arising from climate change.”

Staying near the Baltic coast I very much like cod fishing - with the cutter. About the Baltic cod is here. Cod has 9 subspecies. Cod is the "old" species of fish - has a great adaptive capacity.
According to some evolutionists - gene mutations provide adaptation - almost immediately - to the very rapid climate change, there is always a population of significant size This rapid change in the environment gives them mutations - "asleep" mutations accumulated in the population - “the chances”.

It was found that species such as plants that bloom in the wild in only one color genes are virtually all colors. This is called "black & white cow effect" - which never occurred in nature.

Moreover, it is worth noting that the maps - the location of many economically important species of marine organisms in this presentation (for example, slide 9 - No 13 Atlantic Cod) - waters are often the lowest pH .
Perhaps it is coincidence - areas of low pH is usually also fertile areas for reasons other than pH: estuaries, shallow shelf, upwelling zones, etc. . However, it is known that eg the availability of many microelements (eg iron, manganese) strongly increases at a pH below 7.5. Lowering the pH can - in many areas of large surface - to increase NPP. Powerful ocean areas (up to 75% of the area) with a higher pH are “biological deserts” (as compared to those with a lower pH).

In addition, remember that laboratory testing are not always confirmed by experiments in the environment. This was the case with cod and temperature.
“ScienceDaily (Apr. 29, 2006) — Scientists at CEFAS (UK) have found that the migration pattern of wild cod is much less restricted by environmental temperature than laboratory studies suggest.”
“... scientists following movements of wild cod equipped with electronic tags that record depth and temperature have found that whilst some fish prefer deeper cooler waters, others tagged at the same time prefer to swim in shallower habitats in the Southern North Sea where summer temperatures are consistently above 17ºC. [in the experiments it was: 11-15 ºC]”

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Moderator Response: Please try be brief and on topic. Your theories of everything are, shall we say, difficult to follow.[Doug]

The results of the cod project that Arkadiusz refers to can be found here:

http://www.codyssey.co.uk/

I think it should be pointed out that the research wasn't designed to investigate whether overall increases in temperature would be acceptable (eg increases across the board). In fact the site gives the impression that cod rested in the warmer temperatures, eg didn't feed.

We can suppose the adaptative capacity of a species has some relations with its fertility rate (time of generation and offsprings number by generation) in a context of environmental stress.

Are there long-term experiments where the pH has been gradually rather that abruptly increased ? For example, each generation undergoes the equivalent effect on pH of +50 ppm, and so forth until a doubling or quadrupling. This would permit to observe more precisely the fertility rate of surviving individuals at each generation, and eventually to search some genetic / phenotypic specificities explaining the adaptation for those who survive and reproduce after the pH stress.

I'd be surprised if people are not trying something like that, but such selection experiments are extremely challenging logistically. I know people involved in running them. It will take some several years - maybe a decade - before we see them show up in the literature.

Mace @ 19 - we don't know enough about the Cambrian (some half a billion years ago) to be absolutely sure about the ocean pH back then, and it can't be calculated from atmospheric CO2 alone. There is huge uncertainty about atmospheric CO2 concentrations that far back, and the estimates come from models, with few actual proxies. An additional consideration is that slow changes would allow the ocean to mix CO2 (and the resulting chemical changes) down to the deep ocean, diluting and therefore minimizing the drop in pH at the ocean surface. All-in-all it's a big question mark.

The fact that life was actually blossoming at this time (the Cambrian Explosion) suggests the oceans can't have been inhospitable to life.

In relation to the fake-skeptic canard of higher levels of CO2 in the past, I'm writing up the basic/intermediate/advanced versions of that rebuttal. Simple version = rapid rises in atmospheric CO2 lead to ocean acidificaton, whereas slow changes do not.

Of course none of this has any bearing on species living today, especially the two fish species investigated here. They die when pH drops significantly, that's an observation - no modelling or interpretation of fossils required.

This is a concern given the current rate of change in atmospheric CO2 is 5-27 times greater than the Paleocene-Eocene Thermal Maximum (as pointed out by the moderator above) and around 18-30 times faster than the Permian extinction (around 250 million years ago) also known as the Great Dying because over 90% of life on Earth went extinct.

None of this means we are going to see a repeat extinction event, but at the very least it does suggest a monumental struggle for species to survive. Many will simply not make the grade.

I suggest you avail yourself of the OA is not OK series to gain a better understanding of this rather ominous threat.

skeptic-deniers can point to the spikes that occurred during the pleistocene period as being greater than what happened today,

In the first place, "skeptic-deniers" have proven repeatedly that they will believe -- or at least say -- just about anything to avoid confronting the reality of AGW. That being the case, I don't think there's any reliable way to "skeptic"-proof graphs (beyond following existing standards for scientific practice). If all else fails, they'll find a way to attack the attempt to make graphs "skeptic"-proof. Any port in a storm, as the saying is.

"Skeptics" who point to the Pleistocene ignore the current rate of temperature change, and they also ignore the fact that the Earth now has a population of about 7 billion people (and growing) who are more or less dependent on the environmental status quo. The proper response to the claim you bring up is to point out that it's irrelevant to modern civilization, its infrastructure, its fisheries, blah blah blah. Anyone who can't see that has a vested interest in not seeing it.

Actually, there has been no time in the Pleistocene Epoch where CO2 levels rose above 300 ppm (so "spiked" from 285 to 300 is a bit of a stretch), but it does hint at exactly how deadly what we are doing to the atmosphere may be.

During the Eemian, an interglacial period that began roughly 130,000 years ago and lasted 16,000 years, temperatures in Europe north of the Alps were roughly 1-2˚C higher than today. Sea levels were 4 to 6 meters higher. CO2 levels were roughly at 300 ppm.

Going further back, during a warm period 3 million years ago within the Pliocene epoch, temperatures were a mere 2-3˚C warmer than today (see here and here and here). Sea levels were 25 meters higher. CO2 levels were between 360 ppm and 400 ppm.

John Russell@18 Thanks for the link to the pdf on OA. It really opened my eyes to a problem I have read about, but did not understand at all clearly. Near the end of the document, there is a chart showing various CO2 mitigation strategies we could implement and one of them is shown as 'BECS', which I googled and the best match I found was "Bio Energy to Carbon Sequestration": would that be right?

I am alarmed at the lag in OA vs CO2 increase, meaning that OA is going to increase for a long time, even if we stop pumping CO2 into the atmosphere today. Evidently, there are no brakes on our steam-roller. Good thing I am not fond of sea-food: perhaps that is a benign genetic mutation for me (grin).

Something to keep in mind is that the human impact being wraught on the marine milieu involves changes to thermal, oxic, sonic, and olfactory conditions, as well as to hydronium ion concentration. These impacts combined represent a challenge to many species, and to other species who rely on the former for whatever ecological reason.

As Doug H says, we've started a steam roller and it won't be braking any time soon.

I think the experiments above were pointless, who didnt know if you keep seafish in almost neutral water they would die and produce deoformed fry especially when they havent had 96 years to adapt to the change?

Vonnegut, even if something looks obvious, it still needs to be confirmed via the scientific method. There is a variety of information discoverable well beyond the basic confirmation or rejection of the primary hypothesis.

To me, it's obvious that anthropogenic global warming is occurring and that humans are overhwlemingly responsible for the trend of the last 50 years. So why are we paying these scientists to work out the details. How pointless!

vonnegut, how could fish adapt to the change in as little as only 96 years?

The inland silverside is a fish that lives in estuaries and freshwater, this to me at least makes it surprising that OA proved to be such a problem for them. The fact that the work was published in a journal suggests that the outcome was non-obvious and the experiments were not pointless.

I should point out again that your posting style is not going to work well here, dismissing scientific research as pointless without paing attention to details (such as the natural habitat of the inland silverside) does not give confidence.

vonnegut wrote "the same way they adapt to changes in Ph and temp every day? bit by bit."

This is the same discussion we had on the other thread, just because X is tolerant to short term variations in Y does not imply that X is tolerant of long term changes in Y of similar magnitude. As I pointed out on the other thread, UK native fauna and flora can quite happily adapt to a diurnal and seasonal temperature changes of 15 degrees C, not much of it could adapt to a permanent change of 15 degrees C.

vonnegut wrote "youre suggesting that its harder to adapt over time than it is day by day?"

No, I am saying that oscillatory vairiablity is easier to adapt to than long term effectively permanent change. I would have thought that was obvious from my contrasting "diurnal and seasonal temperature changes" with "permanent change".

I notice that on this thread again you are ignoring the example I gave. Do you think that UK native flora and fauna could adapt to a permanent drop of 15 degrees C in temperature, yes or no?

Second thoughts, I have gone back to thinking you are just trolling. You have no basis for saying that "0.1 ph rise is nowhere near the same as a 15 degree rise in mean tem". pHs and temperatures are not directly comparable without reference to the effects they have on the environment. UK flora and fauna has no problem with a 15 degree C daily variability, fish have no problem with a daily or seasonal 0.1 change in pH. That doesn't mean that fish can cope with a permanent change of 0.1 in pH and more than UK flora and fauna can deal with a permanent change of 15 degrees C in mean temperature.

The real slice of baloney though is the comment about the inuit. Sure inuit can adapt, but you may have noticed that the flora and fauna they encounter is rather different to the flora and fauna you are likely to encounter in the U.K. Do you think that just possibly the difference in mean temperature might be the reason?

Sorry, life is too short for this sort of persiflage when genuine discussion of the science is so much more interesting.

Vonnegut, you seem to be searching for something that allows you to say, "gotcha!" and then walk away. If you were actually trying to understand how it all works, you'd lose the "you're so dumb" attitude and read over both the entire OA is not OK series and some of the more comprehensive studies, starting with Honisch et al. 2012. You'd then say, "ok, this is how I understand it . . . am I right?"

Instead, you're saying, "Ok, this is how I understand it, and I don't really care for your amateurish opinion on my understanding. It's clear that this is not happening or is not a problem. No, I don't need evidence. Or, rather, I need only need evidence to the extent that the evidence supports my pre-existing opinion."

I'll also point out that it's fine to play devil's advocate (e.g. "but what about X?"), but it's not ok to attach subtext that argues that scientists don't know what they're talking about and/or are engaged in fraud. You can draw those conclusions once you've read the existing research and have evidence that fraud is taking place. Until then, lose the accusatory rhetoric.